JPH0437366B2 - - Google Patents

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is a method in which a plurality of electrodes are installed upright in a fuel tank storing fuel such as gasoline or light oil, and the capacitance between the electrodes is determined by the liquid level of the fuel. This invention relates to a fuel level sensor that detects the fuel level based on changes in the fuel level.

"Prior art" As a conventional fuel level sensor, for example,
There is one shown in Publication No. 57-70121.

That is, a pair of electrode plates with opposing electrode plates is placed in a fuel tank, the capacitance created in the gap between the electrode plates is converted into a frequency by an oscillation circuit, and the frequency is measured. In an electrostatic fuel gauge that measures residual fuel in a fuel tank, the electrode gap is made wide enough to prevent water from adhering to it, and the measuring means averages the frequency of the remaining fuel from the oscillation circuit. It is known that the capacitance between the electrodes is proportional to the relative dielectric constant of the material existing between the electrodes, and in general, the capacitance between the electrodes is Since the dielectric constant is larger than that of air, the change in capacitance caused by the difference in the amount of fuel interposed between the electrodes is used as the intermediate value of the fuel level sensor.

However, such conventional fuel level sensors rely on iron as electrodes, are heavy and
Unlike aluminum, it is difficult to ensure insulation, making it the first
As shown in the figure, if the gap between electrodes A and A is made smaller, moisture B will be mixed into the fuel tank along with the fuel.
will adhere between electrodes A and A, causing an error in the change in capacitance. Therefore, to prevent moisture B from adhering, increase the gap between electrodes A and A, and instead make electrodes A and A wider. However, the problem was that it became very heavy and difficult to make smaller and lighter.

``Object of the Invention'' The present invention has been made by focusing on such conventional problems, and solves the above problems by forming each electrode with aluminum and making it easier to form an alumite treatment layer, which is an insulating layer. It aims to solve the problem.

"Structure of the Invention" In order to achieve the above object, the present invention provides a fuel level sensor characterized in that each electrode is formed of an aluminum material and an alumite treatment layer is formed on the surface of each electrode. By using aluminum for the electrodes, the weight is reduced, and by forming an alumite treatment layer, errors in detected values do not occur even if the gap between each electrode is reduced, so each electrode can be made smaller and more compact. This allows it to be made smaller and lighter.

"Embodiment" Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIGS. 2 and 3 show an embodiment of the present invention, and as shown in FIG. It has been done.

The electrodes 2, 2 have their upper ends 21 hanging down from the upper wall 11 of the fuel tank 1 via the support base 3, are supported vertically within the fuel tank 1, and protrude above the upper wall 11. Electric wires 32, 32 for signal transmission are extended from the terminal portion 31 to a display portion (not shown).

As shown in FIG. 3, the electrode 2 has an alumite treatment layer 23 formed on the outer circumferential surface of an aluminum base material 22, and the spacing S between the electrodes 2 is quite narrow, making it necessary to The width of the electrode 2 for obtaining a change in capacitance is small.
As shown in FIG. 2, moisture B can adhere between the electrodes 2 and 2.

In the fuel level sensor having the above configuration, when the level of fuel F in the fuel tank 1 changes, the electrodes 2, 2
Since the amount of fuel F interposed in between changes, the capacitance between the electrodes 2 and 2 changes, and this causes the amount of fuel F to change.
By detecting the liquid level of the fuel F and transmitting the signal to the display section through the electric wires 32, 32, the liquid level of the fuel F can be known. Since the space between the electrodes 2 and 2 is narrow, moisture B will enter between them, but since the alumite treatment layer, which is a non-conductor, is provided, the electrodes 2 and 2 will not be electrically conductive, and this will have no effect on the capacitance between the electrodes 2 and 2. is weak and does not cause detection errors.

"Effects of the Invention" According to the fuel level sensor according to the present invention, not only can the weight be reduced by forming the electrode with an aluminum material, but also an alumite treatment layer, which is a non-conductor, is formed on the surface of the electrode. Therefore, there is no need to consider the adverse effects of moisture, and the spacing between the electrodes can be reduced, which allows the width of the electrodes to obtain the required change in capacitance to be smaller than before. It is possible to provide a fuel level sensor that is much smaller and lighter than the present invention.

[Brief explanation of drawings]

Fig. 1 is a partial front view showing a comparative example when the distance between the electrodes is reduced, Figs. 2 and 3 show an embodiment of the present invention, and Fig. 2 is a vertical sectional view of a fuel tank;
FIG. 3 is an enlarged view of the portion of FIG. 2. DESCRIPTION OF SYMBOLS 1... Fuel tank, 2... Electrode, 22... Aluminum base material, 23... Alumite treatment layer.

Claims (1)

[Claims] 1 In a fuel level sensor in which a plurality of electrodes are installed upright in a fuel tank and the liquid level is detected by changes in capacitance between the electrodes depending on the fuel liquid level, each electrode is formed of an aluminum material and each electrode is A fuel level sensor characterized in that an alumite treatment layer is formed on the surface of the fuel level sensor.